G47.21

Clinical Causes: Genetic factors influencing the body's internal clock Irregular sleep schedules, especially in teenagers and young adults Certain medical or psychiatric conditions Exposure to bright screens and artificial light late at night Shift work or frequent changes in sleep schedules Environmental factors disrupting natural circadian rhythms

Key Symptoms: Difficulty falling asleep at a conventional bedtime Waking up later in the morning or after a preferred sleep time A consistent delay in sleep phase over time Insomnia symptoms due to difficulty initiating sleep Dependency on alarms or external cues to wake up Daytime sleepiness and fatigue Impaired functioning during morning hours Increased difficulty during weekdays or school/work days

Diagnosis Path: Diagnosis involves a detailed sleep history, sleep diaries, and possibly actigraphy (wearable sleep monitoring). Sleep specialists may recommend polysomnography in certain cases. The key indicator is a persistent delay in sleep onset and wake times that cannot be explained by other sleep disorders or medical conditions. It’s essential to differentiate this disorder from other causes of insomnia or fatigue to determine appropriate management.

Treatment Protocols: Management primarily focuses on establishing healthy sleep habits and controlling environmental factors. Approaches include: - **Chronotherapy:** Gradually adjusting sleep times to align with conventional schedules. - **Light therapy:** Exposure to bright light in the morning to advance the circadian phase. - **Melatonin supplements:** Taken in the early evening to promote earlier sleep onset. - **Consistent sleep schedule:** Maintaining regular sleep and wake times, even on weekends. - **Sleep hygiene practices:** Avoiding screens before bed, creating a comfortable sleep environment, and limiting caffeine or stimulants late in the day. While pharmacological interventions can be considered, they are typically used alongside behavioral modifications and under medical supervision.